This segment (including the dancing) was intended to be silly. That show was at one time one of the highest rated big-budget comedies on TV. CBS had more than enough $$$ to get professional choreographers to make the dancing look good if they wanted to. Obviously, the women in this skit aren't even trying. They did this for laughs.
Every single thing on TV is centralized programming scripted to look exactly the way the people in charge want it to look…including so-called reality shows and also the news. Its always been that way.